Surgeons in many specialties commonly use loupes when doing surgery on delicate structures. The loupes used by surgeons are mounted in the lenses of glasses and are custom made for the individual surgeon, taking into account their corrected vision, interpupillary distance and desired focal distance. Some loupes are attached to a helmet or other device worn on the head. Multiple magnification powers are available. They are most commonly used in plastic surgery, orthopedics surgery, microvascular surgery, and tendon repair surgery.